• Title, Summary, Keyword: Dielectric material

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Study on electro-optical characteristic of FFS mode using LC with a positive dielectric anisotropy according to the magnitude of dielectric anisotropy (양의 액정을 사용하는 FFS mode에서 액정의 유전율 이방성에 따른 전기 광학 특성 연구)

  • An, Young-Joo;Park, Ji-Woong;Jung, Jun-Ho;Lee, Hee-Kyu;Lee, Seung-Eun;Lee, Seung-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.399-400
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    • 2008
  • The light efficiency of fringe-field switching (FFS) mode when using a liquid crystal (LC) with positive dielectric anisotropy was found to be dependent on the magnitude of dielectric anisotropy, such that the lower dielectric anisotropy, the higher. We studied out not only light efficiency but also response time according to dependence on the magnitude of dielectric anisotropy. Rising and decay time became fast and slow respectively according to decreasing the magnitude of dielectric anisotropy. This paper investigates electro-optical characteristic of FFS mode using LC with a positive dielectric anisotropy dependent on the magnitude of dielectric anisotropy of the LC.

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Characteristics of Isolator for material parameter (페라이트 소재변수에 따른 아이솔레이터 특성 연구)

  • Jun, Dong-Suk;Lee, Hong-Yeol;Kim, Dong-Young;Lee, Sang-Seak
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.119-122
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    • 2003
  • This paper describes characteristics for insertion losses of Isolator have an effect on material parameter. One purpose of the paper is to present insertion loss on this resonator for magnetic loss, dielectric loss, magnetic field and saturation magnetization. Another is to study the effect of propeller resonator on response characteristics. In this paper, the analysis and measurement of the response characteristics were carried out for the isolator prototype. The measurement results agreed on the simulation results and acquire insertion loss $0.18\;{\sim}\;0.24dB$, return loss 27dB, isolation 27dB and bandwidth 500MHz on this condition saturation magnetization 550G, dielectric loss 0.0004, magnetic loss 20 and dielectric constant 14.

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열처리온도에 따른 SBN 세라믹 박막의 특성

  • Kim, Jin-Sa;Song, Min-Jong;Park, Geon-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.90-90
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    • 2009
  • The $Sr_{0.7}Bi_{2.3}Nb_2O_9$(SBN) thin films are deposited on Pt-coated electrode($Pt/Ti.SiO_2/Si$) using RF sputtering method. The dielectric constant of SBN thin films were increased with the increase of annealing temperature. The maximum dielectric constant of SBN thin film is obtained by annealing at 700[$^{\circ}C$]. The dielectric constant and dielectric loss had a stable value within -5~+5[V].

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Electrical and Mechanical Properties of Ordered Mesoporous Silica Film with HMDS Treatment

  • Ha, Tae-Jung;Choi, Sun-Gyu;Reddy, A. Sivasankar;Yu, Byoung-Gon;Park, Hyung-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.159-159
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    • 2007
  • In order to reduce a signal delay in ULSI, low resistive metal and intermetal dielectric material of low dielectric constant are required. Ordered mesoporous silica film is proper to intermetal dielectric due to its low dielectric constant and superior mechanical properties. In this study, ordered mesoporous silica films was synthesized using TEOS (tetraethoxysilane) / MTES (methyltriethoxysilane) mixed silica precursor and Brij-$76^{(R)}$ surfactant. These films had the porosity of 40% and dielectric constant of 2.5. To lower dielectric constant, the ordered mesoporous silica films were surface-modified by HMDS (hexamethyldisilazane) treatment. HMDS substituted -OH groups on the surface of silica wall for -Si$(CH_3)_3$ groups. After the HMDS treatment, ordered mesoporous silica films were calcined at various calcination temperatures. Through the investigation, it was concluded that the proper calcination temperature is necessary as aspects of structural, electrical, and mechanical properties.

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Calculation of Field Enhancement Factor in CNT-Cathodes Dependence on Dielectric Constant of Bonding Materials

  • Kim, Tae-Sik;Shin, Heo-Young;Cho, Young-Rae
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.1092-1095
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    • 2005
  • The effect of the dielectric constant (${\varepsilon}$) of bonding materials in screen-printed carbon nanotube cathode on field enhancement factor was investigated using the ANSYS software for high-efficient CNT-cathodes. The field enhancement factor increased with decreasing the dielectric constant and reaching a maximum value when the dielectric constant is 1, the value for a vacuum. This indicates that the best bonding materials for screen-printing CNT cathodes should have a low dielectric constant and this can be used as criteria for selecting bonding materials for use in CNT pastes for high-efficient CNT-cathodes

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Dielectric Properties depending on Bias Voltage in Organic Light-emitting Diodes (유기 발광 소자의 바이어스 전압에 따른 유전 특성)

  • Oh, Yong-Cheul;Lee, Joon-Ung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.11
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    • pp.1038-1042
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    • 2005
  • We have investigated dielectric properties depending on bias voltage in organic light-emitting diodes using 8-hydroxyquinoline aluminum $(Alq_3)$ as an electron transport and emissive material. We analyzed the dielectric properties of organic light-emitting diodes using impedance of characteristics. Impedance characteristics was measured complex impedance Z and phase $\theta$ in the frequency range of 40 Hz to $10^8$ Hz. We obtained complex electrical conductivity, dielectric constant, and loss tangent $(tan\delta)$ of the device at room temperature. From these analyses, we are able to interpret a conduction mechanism and dielectric properties contributed by an interfacial and orientational polarization.

Experimental Investigation on Dielectric and Thermal Characteristics of Nanosized Alumina Filler Added Polyimide Enamel

  • Sugumaran, C. Pugazhendhi
    • Journal of Electrical Engineering and Technology
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    • v.9 no.3
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    • pp.978-983
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    • 2014
  • The polymer nano composite possess good priority recently for engineering applications. Especially the electrical insulating materials attract the high performance of nano composites. In this work the ballmill synthesiation process of nano sized Alumina ($Al_2O_3$), the preparation of new nano composite material with an content of enamel and synthesized Alumina as 1wt%, 3wt% and 5wt%. Experimental investigation has been carried out for the prepared nano composites materials with respect to dielectric parameter measurements such as dielectric loss (tan ${\delta}$), dielectric constant (${\varepsilon}$), dielectric strength under various temperature. The partial discharge level also measured for all the samples and the PD inception voltage is also observed and compared. Weight loss of the material has been analyzed through TGA. It has been experimentally proved that 3wt% of Alumina nano filler added enamel has significant improvement in the dielectric and thermal properties.

Dielectric Properties of Epoxy/Micro-sized Alumina Composite and of Epoxy/Micro-sized/Nano-sized Alumina Composite

  • Park, Jae-Jun
    • Transactions on Electrical and Electronic Materials
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    • v.16 no.6
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    • pp.338-341
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    • 2015
  • Epoxy/micro-sized alumina composite was prepared, and the effects of alumina content on the dielectric properties were investigated in order to develop an insulation material for gas-insulated switchgears (GIS). Nano-sized alumina (average particle size: 30 nm) was also incorporated into the epoxy/micro-sized alumina composite. Dielectric tests were carried out in ASTM D 150, and capacitance (Cp) and dielectric loss (tanδ) were measured. The dielectric constant increased with increasing alumina content in the epoxy/micro-alumina system and the epoxy/micro-alumina/nano-alumina system. As 1,3-diglycidyl glyceryl ether (DGE) content increased, the dielectric constant decreased and dielectric loss increased. This ocurred as a result of the weak electric field enhancement due to homogeneous dispersion of micro- and nano-sized alumina particles in an epoxy composite.

Applications of the Silicone Rubber in EHV Electric Appliances (초고압 전력기기에서의 실리콘 고무 응용)

  • 김영호;지응서;박현득;허근도
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.560-564
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    • 1999
  • In general, the main dielectric materials for EHV electric appliances were epoxy, EPDM and Silicone rubber. The Silicone rubber has been rosed so many among them in EHV appliances in the worldwide, especially in Europe and North America. The reason why it is very stable in the thermal, mechanical and electrical environment. Therefore it is still becoming increasingly widespread in the application of the EHV appliances as a main dielectric material. On this study, investigated about real appliances and tested on basic properties of the Silicone rubber compared to organic dielectric material that is EPDM. At the result, the Silicone rubber is more dominant as main dielectric material for EHV appliances than any other organic polymers.

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Analysis of inverters for coupling resonators of monoblock dielectric band-pass filter (일체형 유전체 대역 통과 필터의 공진기 결합용 인버터 해석)

  • 강종윤;최지원;심성훈;윤석진;김현재;박창엽
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.191-194
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    • 1999
  • Recently, with the rapid development and demand for compactness of portable communications, the requirement for compact and low-cost filter is increasing. One of the methods for reducing size and cost is to use high dielectric constant and low loss dielectric material in filter. The other is new monoblock dielectric band-pass filter (BPF) which has holes in a single dielectric body without additional coupling elements. This structure effectively reduces the size and cost of the filters. For previous conventional coaxial type dielectric BPF, dielectric substrates were used for coupling between adjacent resonators and additional input and output ports were needed. Coupling between adjacent resonators of monoblock BPF can be otained via electrode pairs. Capacitances of electrode pair structure for coupling are intensively investigated by 3-D FEM. The BPF for PCS has been designed to have a 30 MHz pass-bandwidth with center frequency of 1855 MHz and an attenuation pole at below the passband using a commercial 3-D structure simulator.

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